VA - the CR sabots load easier than the standard sabots. I've been using the Green CR (for 430" bullet) using a 300 gr Hornady XTP with right about MOA accuracy using 100 gr of Pyro P. This bullet/sabot combo goes down snug with a steady, even pressure but is not overly tight.
My other ML shoots the 300 gr Shock Waves good with the T/C EZ load sabot. I got some on sale with the std black sabot but they are hard to load. I picked up the Black CR sabots (.451" bullet) but have yet to try them.
As for the shoulder shots, I really don't like them, even with my center fires. I prefer to slip the bullet in behind the shoulder.
However, my theory of shooting deer, and the one that I taught my son is basically to visualize a basketball setting between the deer's shoulder and aim for the center of it or slightly below center. This works regardless of the angle of the deer. If the shoulder is in the way depending on angle, so be it. Using this method, I have yet to loose a deer I shot. Most dropped where they stood.